The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Homogeneous charge compression ignition (HCCI) engines combine aspects of spark ignition (SI) engines and stratified charge compression ignition (SCCI) engines to achieve emissions similar to SI engines and fuel efficiency similar to SCCI engines. In SI engines, air and fuel are mixed together and spark ignites the air-fuel mixture. In SCCI engines, air and fuel are mixed together and combustion occurs at the boundary of the air/fuel mixing due to compression. In HCCI engines, ignition occurs at several places at a time, which combust the air/fuel mixture faster than SI or SCCI engines.
Powertrain control systems and methods have been developed to control powertrain components, such as an engine and an electric motor, in the torque domain to coordinate the torque output of each component. These control systems and methods may estimate the torque produced by SI or SCCI engines. However, these control systems and methods do not estimate the torque produced by HCCI engines.